1. Field of the Invention
The present invention relates to a solid image pickup device, and relates to the solid image pickup device which eliminates noise components, offset components or unnecessary background image components from an obtained image signal to obtain only the necessary image components.
2. Related Background Art
In recent years, with the spread of image processing techniques, various kinds of image pickup devices as a main device having a photoelectric conversion function have been developed. A charge transfer device represented by a CCD or a BBD, a MOS type image pickup device, and a position sensitive detector are examples of the image pickup devices.
In a case that only a certain object is intended to be taken by the image pickup device, not only light from the certain object but also light from its background are incident on the photosensitive unit, so that the light from the background is included in the image signal as noise components. Therefore, it is a problem that the real image signal of the certain object cannot be obtained.
The conventional solid image pickup device employs some technique to eliminate noise components including offset components and noise components generated by the photosensitive unit itself (Japanese Patent Laid-Open No. 59-142412 (142412/1984)).
However, it is not practical to use as the solid image pickup device.